1. Field of the Invention
This invention relates to an image forming apparatus which forms an image by using a developer, and a developer recycle apparatus which returns a developer recovered from an image carrier to a developing device mounted on the image forming apparatus to recycle it as developer.
2. Description of the Related Art
Image forming apparatuses which form an image by using a developer containing, for example, toner, form an electrostatic latent image on a photosensitive drum as an image carrier, develop the electrostatic latent image by a developing device, transfer an obtained toner image to paper being a transferred material to which an image is transferred by a transfer device, and fix the image on the paper by a fixing device.
Among image forming apparatuses of this kind, known are apparatuses which remove toner remaining on the photosensitive drum by a drum cleaning device after the toner image is transferred to the paper, and returns the removed toner (hereinafter referred to as “recycle toner”) to the developing device to recycle it. Further, known is a recycle toner carrying mechanism which carries the recycle toner received from the drum cleaning device to the developing device.
In this process, the drum cleaning device supplies the recycle toner to the recycle toner carrying mechanism without controlling the quantity of the recovered recycle toner. Therefore, there is a fear that the recycle toner adhering to the carrying path in the drum cleaning device comes off by vibration or the like, and that a large quantity of recycle toner is supplied to the recycle toner carrying mechanism at a time.
The large quantity of recycle toner supplied is jammed in a portion connecting the drum cleaning device and the recycle toner carrying mechanism, and causes a problem of blocking the carrying path of the recycle toner. Further, supplying a large quantity of recycle toner to the developing device at a time causes poor imaging (fog).
Further, unlike fresh toner, recycle toner has been subjected to mechanical, thermal and electric stress before being recovered by the drum cleaning device, and thus external additives of the surface of the recycle toner have been come off or buried in the recycle toner. Therefore, the recycle toner has moisture and viscosity, and has flowability much lower than that of fresh toner. This causes a problem that toner jams in the recycle toner carrying device and blocks the carrying path of the recycle toner.
As described above, if the carrying path of the recycle toner is blocked, there is the fear that the blockage is determined as occurrence of error and the apparatus is stopped. This causes the problem of decreasing the working efficiency of the user using the apparatus.